1. Field of the Invention
The present invention relates to imaging apparatus, and more particularly to such apparatus in which a light-valve array is used to produce a continuous-tone image on a recording medium.
2. State of the Prior Art
Various types of imaging apparatus are used to effect the exposure of a recording medium in accordance with information in an electrical signal. For example, in U.S. Pat. No. 4,454,547, there is disclosed an output scanner which comprises a source of high intensity radiation, means for converting radiation from the source to a plurality of individual radiation beams, and an array of flexible reflector fingers which can be positioned in response to an information signal to direct the beams onto an imaging member. The fingers are selectively deflected by an electrostatic force resulting from a voltage imposed on the fingers. A problem with the scanner disclosed in this patent is that it is not adapted to produce a continuous-tone image. When the finger is fully deflected, no light is transmitted to the imaging member, and when the finger is not deflected, the full beam is transmitted to the imaging member.
U.S. Pat. No. 4,378,568, discloses apparatus which utilizes a plurality of light valves to produce a continuous tone image. The light valves are arranged in an array which includes a panel of ferroelectric ceramic material having a plurality of electrodes thereon which can be selectively energized. The light valves used in this apparatus are too slow for certain applications, and relatively complex electronics are required to actuate the light valves.